Method and apparatus for heating



Dec. 15, 1936. WILSON METHOD AND APPARATUS FOR HEATING- Filed June 8, 1935 2 Sheets-Sheet l Z2 97 INVENTOR Patented Dec. I5, 1936 I. it I I UNITED STATES PATENTOFFICE METHOD AND APPARATUS FOR HEATING Lee Wilson, Cleveland, Ohio v Application June 8, 1935, Serial 1:10. 25,624

8 Claims. (01. 266-) My invention relates broadly to the art of heat Figure 3 is a sectional view taken along the line exchanging and, in particular, to the delivery of III-III of Figure 1; heat by a fluid medium. The invention will be Figure 4is a top plan view; 7 described herein as applied to the 'art of heating Figure 5 is a partial transverse sectional view 5 annealing furnaces, although it has other applithrough a furnace having the invention applied 5 cations. thereto;

In my United States Patent No. 1,952,402, I have Figure 6 is a partial longitudinal section taken illustrated an annealing furnace of the so-called along the line VI--VI of Figure 5;

bell or cover type, including a base and a cover Figure 7 is'a view similar to Figure 3 showing a disposable thereon, the cover being provided with a modified form of the invention; 10 a plurality of heat-exchange tubes through Figure 8 is a similar sectional view showing-a which hot combustion gases are circulated to heat different arrangement of heat-exchangetube; the interior of the cover. The hot combustion Figure 9 is a sectional view along, the line gases are supplied to the tubes adjacent the bot- IX--IX of Figure 8; and tom of the cover and flow upwardly therethrough. Figure 10 is a sectional view showing a further 15 Because of the tendency of the gases within the modified mounting of the heat-exchange tube. furnace to rise when heated, I find that the upper Referring now in detail to the drawings and,

part of a charge disposed within the furnace for for the moment, to Figures 1 through 6, I provide annealing is heated to a temperature higher than a heat-exchange element III comprising a tube II the bottom portions thereof. This causes the closed upon itself in substantially the form of an 20 product to lack the highly desirable quality of oval, having straightportions I2 and I3 connected uniformity in characteristics. by elbows i4 and I5. The heat-exchange tube I I I have invented a method and apparatus for may also be conceived as composed of a pair of heating which overcomes the aforementioned ob- U-shaped tubes disposed end to end. The tube jection and is characterized by additional novel II is adapted for mounting adjacent the wall of and advantageous features. In accordance with an enclosure to beheated. Such a wall is indimy invention, I in r c t heat-conveying fluid cated in chain lines at I6 and may be the wall of adjacent the middle of the side wall of the furnace a furnace or any other-suitable enclosure.

or other enclosure to be heated, circulate portions Adjacent the mid-point of one of the straight 3 thereof in pp directions m the point of sections of the tube H, such as that shown at; I2,

- delivery, and independently control the fiow of is the means for supplying heated fluid to said such portions to regulate the amount of heat de-' portion for flow in opposite directions therealong.

liVered to Various portions of p ce e g As an example of such means, I have shown a gas heated. The apparatus of my invention includes burner I'I projecting into a nipple I8 communiplurality 0f heat-exchange tubes mO mtEd n eating with the straight portion I2 of the tube'II.

the furnace or the space to be heated, each tube The burner II supplies fuel for combustion in the having means adjacent its middle for supplying nipple I8 and the'tube II with the air induced, heated fluid thereto for fiow in opposite directions thereby into the nipple. The combustion gases therealong. In a specific form of the invention, I fiow in opposite directions along the straight por- 40 employ heat-exchange tubes which are closed tion I2 of the tube II and thence around the el- 40 upon themselves in substantially the form of an bows I4 and I5 and along the'straight portion I3. oval, and dispose a burner at about the middle of The other straight portion I3 of the tube II one of the straight sections of the oval, and an is provided with an exhaust pipe I9 extending exhaust at a corresponding position on the other outwardly through the wall IS. The pipe I9 has straight portion. The oval heat-exchange tubes a central partition 20 separating opposite ends of -may also be conceived of as a pair of U-shaped the straight portion I3 of the tube II. Stacks tubes disposed end to end. 2| and 22 are connected, respectively, to the ducts The accompanying drawings illustratea presformed in the pipe I9 by the partition wall 20,

m preferred embodiment of the invention with The stacks 2| and Z2 have independent dampers certain modifications and a specific application 23 and 24 enclosedtherein which can be ad-- I thereof. In the drawings: justed to control the flow of gases from the Figure 1 is a side elevation of a heat-exchange nipple or inlet pipe I8 in opposite directions tube showing the part in section; through the tube II. If it is found," for ex- Figure 2 is an end elevation; ample, that the upper portion of the tube II, in-

cluding the elbow I5, is delivering an excessive amount of heat, the damper 24 may be closed to restrict the flow -of hot gas therethrough. Similar adjustment of the damper 23 controls the amount of hot gases flowing through the lower part of the tube, 'including the elbow Id. In his way, a highly flexible control of the heat supplied by the upper and lower portions of the tube II is provided. 1

Figures 5 and 6 illustrate the application of the invention to an annealing furnace of the same general type as disclosed in my prior patent aforementioned. The tubes II are preferably disposed side by side along the side walls 25 of the cover 26 of the furnace, although they may be disposed also along the end walls, or even the roof, in accordance with a modification to be described later. The cover 26 is disposable on a .By my. invention, it is thus possible to deliver diiferent amounts of heat at different points along the length of the furnace, as well as to deliver different amounts in the upper and lower portions thereof. A nice control of the annealing operation is thus aflorded, which makes for a product characterized by a high degree of uni-g formity as to all its qualities.

Sand and oil seals 33 and 34 close the joints between the inner cover 29 and the furnace cover 26', respectively, and the base 21. g

Figure 7 illustrates a heat-exchange tube 35 which is similar in general to that shown at ll except that it has dampers 36 and 31 mounted in the exhaust pipe IQ, for controlling the flow of hot gases through the upper and lower portions of the tube. With this arrangement, a single stack 38 is sufiicient to dischargethe combustion gases flowing through both portions of the tube.

Figure 8 shows a tube of the type shown in Figure '7 mounted horizontally. The burner I1 is supplied with fuel from headers 3|. By adjusting the dampers 36 and 31 appropriately, the amount of heat delivered to points adjacent opposite ends of the tube 35 may easily be varied.

Figure 9 further shows the arrangement of the tube 35 in horizontal position.

Figure 10 illustrates the tube 35 mounted in the roof 39 of an enclosure 40 which might be the cover of a cover-type furnace,- or an ordinary annealing furnace with fixed walls and hearth. The exhaust pipe l9 projects through the roof 39. The burner l1 and the nipple I8 projectof control for heating operations which has not beeen attainable heretofore and is particularly applicable to the annealing of material such as sheets in-stacks, where it is necessary that the temperature of the material shall be substantially constant throughout the entire mass.

While 'I have illustrated and. described herein but one preferred embodiment of the invention and the application thereof to a specific problem, that of annealing, and certain modifications, it will be understood that many changes in the method and apparatus described may be made without departing from the spirit of the invention or the scope of the appended claims.

. I claim: .,1. A heat-exchange element comprising a closed tube of substantially oval shape including a pair of straight portions substantially parallel and a pair of elbows connecting them, means for supplying a heat-conveying medium to the tube at a point on one of said straight portions, and an exhaust for said medium at a point spaced from said means.

2. The apparatus defined by claim 1 wherein said means and said exhaust are located on the straight portions, respectively.

3. Heat-exchange apparatus comprising a pair of U-shaped tubes disposed end to end, common means therebetween for supplying a heatconveying medium to said tubes, and means for controlling the flow of said medium through said tubes.

4. In a method of heating a furnace cover having a roof and side walls, the steps including supplying a heating medium to points-inter mediatethe top and bottom of the side walls and diverting flow thereof in opposite directions along said walls.-

5. A furnace comprising a base, a cover disposable therover having side walls and a roof, and heating means mounted inside the cover including a heat-exchange tube, means for delivering hot gases to the tube at a point between the closed on itself in substantially oval form, a

burner discharging thereinto at a point between the curved ends of the oval, an exhaust for gases discharged from the burner at a point between the curved ends of the oval, and independent means for controllingthe flow of. gases in opposite directions from the burner to the ex- 7. In a furnace having a roof and side walls, a heat-exchange element comprising a tube bent and closed upon itselfand mounted on said walls but positioned inwardly thereof, means for supplying a heat-conveying medium to the tube at least one point thereon, and an exhaust for said medium at another point spaced from the first point, providing two paths for flow. of said medium from the point of supply to the exhaust.

8. A furnace asdefined by claim 7 characterized by said heat-exchange element being elongated and disposed with its longer dimension vertical, said means comprising a burner inter" mediate the top and bottom of said element.

LEEWIISONHY 

